Radioimmunoassays of human myoglobin in serum and urine

Abstract

Two solid-phase radioimmunoassays have been developed for the detection of myoglobin in serum and urine. The sensitivity of the methods is 0.1 and 0.5 wg/1, respectively, with a coefficient of variation of the respective method of 7–8%. The mean serum concentration of myoglobin in ninety-nine healthy blood donors was 44.3 μg/1 ± 18.0 μg/1 (SD) with a significant difference (P < 0.001) between men (50.6 ± 19.8) and women (35.7 ± 10.4). Serum myoglobin was positively correlated to age (P < 0.05), body weight (P < 0.02), serum creatine kinase (P < 0.001), and serum creatinine (P < 0.01). In patients with liver failure serum myoglobin was correlated (P < 0.01) to galactose elimination rate. Serum myoglobin levels were not influenced by exhaustive short time dynamic exercise. The mean urinary excretion of myoglobin in twenty-four healthy students was 1.2 μg/24 h (range 0.1–4 μg/24 h). Myoglobin excretion was correlated to excretion of β₂-microglobulin (P < 0.02) but not to serum levels of myoglobin. No indications of circulating antibodies to myoglobin were obtained when assaying sixty-seven rheumatoid arthritis and thirteen myastenia gravis sera. Presence of other myoglobin binding substances in serum, which would interfere with the assays also seemed unlikely. Determination of myoglobin in serum by sensitive and specific method might be of clinical value in the diagnosis of diseases involving muscle tissues.

Key Words:

• autoantibodies
• β₂-microglobulin
• exercise
• liver